Phenylene-bridged binuclear half-metallocene complexes: Synthesis and catalytic reactivity of lanthanide and titanium derivatives.

摘要

In Chapter 1, phenylene-bridged bimetallic organolanthanide complexes p-bis{ Cp''Ln[N(SiHMe2)2 ]2}phenylene [p-Ln2] (Ln = Y, La; Cp'' = tetramethylcyclopentadienyl) and m-bis{Cp''La[N(SiHMe2)2]2 }phenylene [m-La2] are investigated for possible Ln˙˙˙Ln cooperative effects in hydroamination processes. These binuclear organolanthanide complexes efficiently catalyze the intramolecular hydroamination/cyclization of aminoalkenes, aminoalkynes, aminoallenes, and conjugated aminodienes with turnover frequencies as high as 10 h-1 at 60 °C, as well as intermolecular hydroaminations with turnover frequencies as high as 0.4 h-1 at 90 °C. Substrates include those having both compressed and extended junctures between the C-C unsaturation and the --NH2 group, as well as those with multiple --NH 2 groups or places of C-C unsaturation. Reactivity trends appear to be dominated by non-bonded repulsive interactions, resulting in catalytic activities following the general trend m-Ln 2 p-Ln2. Organolanthanide amide complexes are also shown to catalyze the prototropic isomerization of alkynes.;Chapter 2 presents that the binuclear half-titanocene complex p-bis{eta5-(2,3,4,5-tetramethylcyclopentadienyl)TiCl 3}phenylene has been synthesized via the isopropoxide derivative, p-bis{eta5-(2,3,4,5-tetramethylcyclopentadienyl)Ti(O iPr)3}phenylene. When activated with MAO, this binuclear complex is a highly active and highly syndiospecific catalyst for the polymerization of styrene with activities up to 100.6 kg polymer/(mol Ti x hr) at room temperature.